The invention relates to a computed tomography method for forming images of an object to be examined which is arranged in an examination zone, which method includes the steps of:                generating, while using an X-ray source, a conical X-ray beam which traverses the examination zone or the object to be examined which is arranged therein,        rotating the X-ray source and an oppositely situated X-ray detector on the other side of the examination zone along a trajectory around the examination zone,        acquiring projection data by means of the X-ray detector during the rotation,        reconstructing one or more images from the projection data.        
The invention also relates to a corresponding computed tomography apparatus, notably an apparatus for carrying out such a computed tomography method.
A method of this kind is known from EP 0 990 892 A2. In order to reduce the computational effort required for the reconstruction of the absorption distribution in the examination zone, the cited document proposes to perform rebinning of measuring data so as to form a number of groups, to subject said data to one-dimensional filtering, and to reconstruct the spatial distribution of the absorption from the filtered data of different groups.
Future cone beam computed tomography systems will enable the formation of high-resolution 3D images from the acquired projection data. Moreover, the physician will additionally be offered novel possibilities for viewing. It will inter alia be possible to select a plane of arbitrary orientation in the examination zone wherefrom data was acquired and to form a slice image which is situated in said plane from the data available. Such a slice image in the desired plane is formed by interpolation of the 3D image data which constitutes a complete 3D image data set resulting from the reconstruction of the acquired projection data. Such an interpolation of 3D image data, however, gives rise to a pronounced deterioration of the image quality of such a slice image.